1. Field of the Invention
The present invention relates to a control method for a dog clutch that transmits a torque by meshing and a control device for a dog clutch.
2. Description of Related Art
A dog clutch that can transmit a torque by meshing is used to lock (differentially lock) a differential action between a pair of side gears of a differential device of a vehicle, for example (e.g., see Japanese Patent Application Publication No. 2006-29579 (JP 2006-29579 A)).
The differential device described in JP 2006-29579 A includes an electromagnetic coil, a plunger that moves due to a magnetic force of the electromagnetic coil, and a clutch ring having meshing teeth configured to mesh with one side gear out of the pair of side gears, as a structure to lock the differential action between the pair of side gears. When a current is applied to the electromagnetic coil, the meshing teeth of the clutch ring mesh with the one side gear along with a movement of the plunger, so that a relative rotation between a differential case and the one side gear is restricted. Accordingly, a pair of pinion gears pivotally supported by a pinion shaft rotating integrally with the differential case cannot rotate, so that the differential action between the one side gear and the other side gear is restricted.
When a differential-lock operation switch operated by a driver enters an ON state, a control device for controlling the differential device supplies an exciting current to the electromagnetic coil. The control device detects by a signal of a position switch that the meshing teeth of the clutch ring mesh with the one side gear. The control device is configured such that, when the meshing is detected, the control device starts a timer, and when a timer value reaches a predetermined threshold, the control device decreases a current to be supplied to the electromagnetic coil from a current necessary to mesh the clutch ring to a relatively small current to such an extent that a meshing state is maintained.